Over time, smartphones have become more capable and their use has increased. With the increasing use of smartphones for everyday tasks also comes the increasing risk of losing sensitive data. One way to protect against such loss is the use of a lock screen to secure a smartphone. A lock screen can be built into the phone (i.e., a “default” lock screen) or it can be a separate application that may be obtained from third parties. While lock screens can provide some security, many users are not satisfied with currently available lock screens. They either provide too little security or require too much effort to be unlocked. Additionally, conventional lock screens that are based on gesture recognition typically suffer from the weakness that if the gesture data is collected from a wet surface or using greasy fingers, the lock screen becomes unusable.